Generally, many parts including an engine in heavy equipment such as a wheel loader, an excavator, etc. are covered by an engine hood with the engine being adapted therein to generate a certain driving force. When a part of the engine needs an exchange or maintenance, the door is opened and supported by a certain support member such as a rod so as to obtain a desired safe work in a state that the door is opened.
FIG. 1 is a perspective view illustrating a conventional locking and unlocking apparatus of an engine hood door, and FIGS. 2 and 3 are enlarged views of the conventional locking and unlocking apparatus.
As shown in FIG. 1, an engine hood 10 covers various parts such as an engine, etc. and includes a frame 20 having an opening 12 at an upper surface, and a door 40 which is hinged at one side of the frame 20 and rotates upwards and downwards about a hinge shaft 30 for thereby opening and closing the opening 12. A guide bracket 22 is fixed at both sides of the opening 12 of the frame 20, with the guide bracket having an angle shaped cross section. An upper surface of the guide bracket 22 is engaged to the frame 20 using a bolt. A guide rail 24 is formed at a side surface of the guide bracket 22. As shown in FIG. 2, a guide groove 26 is horizontally formed at the guide rail 24 in a longitudinal direction of the guide bracket 22. A fixing groove 28 is formed at an end portion of the guide groove 26 in a step shape.
As shown in FIG. 3, a guide rod 42 is slide-movable along the guide rail 24. A guide roller 44 is provided between the guide rail 24 and the guide rod 42 so that the guide rod 42 can smoothly move.
When the door is pulled with one hand holding a handle 46, the guide roller 44 at a front end of the guide groove 26 slides along the guide rail 24, and the door 40 is hinge-rotated upwards about the hinge shaft 30 and is opened. Here, since the guide roller 44 is fixedly mounted at the fixing groove 28, the guide rod 42 supports the door 40 in an upward direction.
With one hand holding the handle 46, and with the other hand holding the guide rod 42, the guide roller 44 is separated from the fixing groove 28 and is moved to the guide groove 26, the guide roller 44 slides from the rear end of the guide groove 26 to the front end of the guide groove 26, so that the door 40 is hinge-rotated downwards about the hinge shaft 30 and is closed.
However, the above conventional locking and unlocking apparatus of an engine hood door has the following problems.
For the movement of the guide roller 44 from the fixing groove 28 to the guide groove 26, the user should touch the guide rod 42 by hands. Therefore, the user's hands may be polluted by various pollutants such as sooty, dusts, etc. attached on the guide roller 42 in the interior of an engine chamber. When a strong wind is blown to the door or an external impact is applied thereto, the guide roller 42 may be severely vibrated, leading to an uncomfortable state to a user.
A certain noise may occur due to a gap between the guide groove 26 and the guide roller 44 while the guide roller 44 slides along the guide rail 24. Since the guide roller 44 slides in contact with the guide rail 24 when opening and closing the door 40, the painted surface of the guide bracket 22 may be peeled out, so that the guide bracket 22 may rust.